This is for all the large bore K161 engines including K161A, K161AS, K161AQS or any k161 with any suffix on it.Pistons. Please note the cylinder chart below, kohler made the early small bore and the later large bore. If you have the small bore, they do not make that piston any longer. You have to purchase the large bore standard 2.9375 inch bore piston and have the machine shop bore to match.
Rods, Please note.. The K161 rod is 4 1/4 inches (crank pin to wrist pin) center to center and about 7 7/8 in long
The K181 rod is 4 inches (crank pin to wrist pin) center to center and about 7 1/2 in long.
If you have the longer rod, you have a K161, if you have the shorter rod you have a 8hp K181